We are requesting funds for the acquisition of a BD FACSAria II Cell-sorting instrument. The researchers on the Science Hill campus of Yale University have extensive microscopy experience for their cell, stem cell and developmental biology research programs. These users would like to extend their extensive microscopy experience studying cell and developmental biology questions to use flow cytometry analyses for quantitative analysis of cell populations and cell isolation for clonal studies. The availability of this state-of-the-art flow cytometry instrument would heighten the research of users of this proposal by allowing quantitative analysis of the expression of up to 10 fluorescently labeled molecules and/or antibody stained proteins in large populations of cells. Furthermore, this instrument will allow users to isolate up to 4 individual labeled populations of cells via cell sorting to use for various applications such as population analysis of clonal behavior in cell culture, of gene expression by RNA isolation, etc. The proposed instrument will be the only machine capable of modern multi-color analysis and cell sorting on the Science Hill campus of Yale University. The availability of this instrument on Science Hill will allow complex and cutting edge experiments to be performed using flow cytometry by making it an efficient and accessible technique to support the strong cell biology, stem cell, and developmental biology programs in multiple model organisms including chicken, mouse, zebrafish, yeast and bacteria. Research activities facilitated by this instrument will include the investigation of asymmetric cell division and self-renewal in neural stem cells (Weimin Zhong, PI), cytoskeleton and molecular motors (Mark Mooseker), biological networks (Thierry Emonet), origin and induction of neural crest stem cells (Martin Garcia-Castro), zebrafish somitogenesis (Scott Holley), maintenance and control of epithelial stem cells (Valerie Horsley), cytoskeletal dynamics and cellular motility (Tom Pollard), cell cycle regulation (Hochstrasser and Solomon) and axonal, dendritic and spinal abnormalities in neuronal developmental defects (Elke Stein). PUBLIC HEALTH RELEVANCE: The requested state-of-the-art instrument will have a significant impact on the research programs on the Science Hill side of the Yale campus by filling a significant void in our available instrumentation. Given the need to quantitatively analyze and isolate populations of cells in order to examine the complexities of biological processes, access to a state-of-the-art flow cytometry and cell sorting instrument will maximize the impact of currently funded NIH research.